Polarized radiation emitting element for inclusion as a light source in an electric lamp



SMRCH R! Jail 3, 19k N. AGDUR ETAL 3,296,482

POLARIZED RADIATION EMITTING ELEMENT FOR INCLUSION AS A LIGHT SOURCE IN AN ELECTRIC LAMP V Filed Dec. 18, 1963 @mi/M United States Patent O PLARIZED RADIATlON EMITTING ELEMENT FOR INCLUSIN AS A LIGHT SOURCE 1N AN ELECTRIC LAMP t Nils Berti! Agdur, Danderyrl, Florian Sellberg, Dyursholm, Kurt Goran Rafael Bolling, Taby, and Kari Yngve Qhman, Stockholm, Sweden, assignors to Kooperativa Forbundet Ekonomisk Forening, Stockholm, Sweden Filed Dec. 18, 1963, Ser. No. 331,416 Claims priority, application Sweden, Dec. 22, 1962, 13,846/ 62 16 Claims. (Cl. 313-341) This invention relates to the production and emission of polarized radiation and, more particularly, to lightemitting filaments or other elements for inclusion in or with various lamps for producing polarized light radiation directly in polarized condition as emitted and without polarizing filters and the like.

As will be understood, the practical production of polarized light conventionally requires, in one form or another, some sort of filter in association with the light source for producing or transmitting only polarized light from the nonpolarized light conventionally produced. In addition to requiring extra expense for such filters and other apparatus, the production of polarized light by filtering, instead of generating or emitting the light in a polarized fashion in the first place from the light source, reduces substantially the efficiency of the light source itself.

According to this invention, however, there are provided elongated light-emitting elements having in various forms a transverse dimension correlated with and generally of the same order of magnitude as the wave length of light desired to be emitted, and, preferably, with such elongated elements (or successive portions thereof) arranged in generally side-by-side but spaced relation with the spaces between adjacent elements or portions thereof also being correlated with and generally of the same order of magnitude as the wave length of the light desired to be produced. Additionally, and as further features of this invention, there are provided a variety of manners and means for the disposition and supporting of such light-emitting elements for the inclusion or association thereof in or with incandescent or gas discharge or other types of electric lamps-all to the end of providing a light-emitting source or element utilizing the full eiciency and productivity of electric current therein for producing and emitting light of a predetermined wave length and polarized as emitted or produced.

With the foregoing and additional objects in view, this invention and several embodiments thereof will be described in more detail, and other objects and advantages of this invention will be apparent from the fol- `lowing description, the accompanying drawing, and the appended claims.

In the drawing, all figures of which are highly schematic or diagrammatic in view of the fact that the exceedingly small dimensions involved are not readily susceptible to realistically representational illustration:

FIG. l illustrates one embodiment of light-emitting elements embodying and for practicing this invention and arranged on a generally flat support;

FIG. 2 illustrates another embodiment of this invention similar to FIG. l but with the light-emitting elements arranged axially on a cylindrical support;

FIG. 3 illustrates a further embodiment or arrangement for practicing this invention in which the lightemitting elements are applied or fabricated on to a cylindrical support;

FIG. 4 illustrates a further embodiment or arrange- 3,296,482 Patented Jan. 35, 1967 ICC ment for practicing this invention in which the elongated light-emitting element is a tiny wire wound helically around a larger wire support in, for example, the formation of a filament for a lamp bulb;

FIG. 5 illustrates a further embodiment or arrangement for practicing this invention in which the lightemitting elements are arranged as successive plates or discs of varying dimensional or refractive characteristics in spaced disposition to form the light-emitting device; and

FiG. 6 illustrates a further embodiment or arrangement for practicing this invention in which the polarizing lightemitting elements are indicated as applied to a gas discharge light source.

Referring to the drawings, which illustrate a variety of embodiments of this invention or arrangements for the practicing thereof, one arrangement is illustrated in FIG. l as comprising a plurality of light-emitting elements supported on a more or less fiat or planar base 10 having on one surface thereof a plurality of ridges, three of which are designated as 11, 12, and 13 in the drawings, spaced apart and having a substantially rectilinear crosssection. As illustrated, each of the ridges 11, 12, 13, etc., has a transverse dimension d approximately equal to or, in any event, of the same order of magnitude as the wave-length of the radiation desired to be emitted from the several elongated light-emission elements or ridges 11, 12, 13, etc. Actually, as the dimension d decreases and approaches precisely the wave-length of light desired, the luminous efficiency of the entire plurality of light-emitting elements increases, with the light emitted thereby being of a polarized nature as desired and in the absence of filters or other efliciency reducing apparatus.

As will be understood, electromagnetic or light-wave energy is produced by the several light-emitting elements or ridges 11, 12, 13, etc., as by heating plate 10-for example, as by passing an electric current through it by means of electrical conductors indicated diagrammatically at 14, in this instance with the current passing in a direction perpendicular to the axes of the several light-emitting elements or ridges. Thus, because of this particular orientation and design of the light-emitting elements or ridges, the plasma resonance properties thereof will guide the vibration direction of thermic emission vibrations so that a strong polarization occurs in the radiation emitted from the illustrated arrangement.

Furthermore, and in a preferred manner in accordance herewith, the several light-emitting elements or ridges 11, 12, 13, etc., are disposed as spaced apart on plate 10 by a distance substantially equal to the dimension d, in which manner polarization of emissions of the grooves themselves reinforces or partakes of the same polarized direction as the polarized radiation of ridges 11, 12, 13, etc., thereby further increasing both the emissive or luminous efciency of the entire arrangement and controlling substantially all the radiation therefrom to be polarized in the same direction. As with conventional or other incandescent lamp filament or light-emitting elements or sources, the plate 16 and ridges 11, 12, 13, etc., thereon are satisfactorily made of such high resistivity materials as tungsten, molybdenum, platinum, etc., while the actual production of the specific arrangement illustrated in FIG. 1 is satisfactorily obtained as by etching from a unitary plate the upstanding ridges and grooves therebetween in the appropriate dimension, depending upon the wave length of radiation desired. For example, satisfactory results are achieved in accordance with the illustrated embodiment when the dimension d is equal to or the same order of magnitude as the radiation wave length-e.g., of the order of perhaps 1-2 microns or lesswhile the number of ridges 11, 12, 13, etc. (or of the corresponding elements described in connection with the other embodiments disclosed hereafter), are satisfactorily at least of the order of l or more as included within an incandescent light bulb source in order to give appropriate high polarization of emitted radiation within the optical range as desired.

As further illustrated in FIG. 2, the substrate or support 10 need not be flat or planar, but may take on a cylindrical form such as 20, as a rod or wire into which are etched or otherwise formed grooves to provide ridges such as 21, 22, 23, etc., therearound. Such ridges, as will be understood, may run circumferentially or helically around cylindrical substrate 20 or, as illustrated in FIG. 2, may run axially therealong. In any event, the dimensioning thereof, and preferably, of the grooves therebetween, is correlated with the wave length of the radiation to be produced or emitted thereby in polarized form, as previously explained with regard to the embodiment of FIG. 1.

As will be understood from the foregoing, the various ridges 11, 12, 13, etc., and/or 21, 22, 23, etc., need not necessarily be integral with or of the same material as base 10 or 20. Thus, satisfactory results in accordance herewith are achieved with an embodiment such as illustrated in FIG. 3, where the light-emitting elements are a plurality of wires 31, 32, 33, etc., around a substrate or support 30 (or along a flat plate somewhat in the manner of FIG. 1) with energy emission being produced by heating wires 31, 32, 33, etc., by conduction from support 30 being heated as by an electric current through conductors 34 and/ or, as will be understood, with wires 31, 32, 33, etc., being directly connected into the principal electric circuit (in which event, support 30 need not be electricity conducting). Then, in any event, the diameter d of wires 31, 32, 33, etc., is selected to be approximately equal to or the same order of magnitude as the wave length of the radiation desired to be emitted and, when the support 30 is connected in the circuit for heating the wires, that portion of the radiation directly emitted from support 30 is also preferably polarized in the same direction as that emitted by wires 31, 32, 33, etc. as by maintaining the spaces between adjacent wires also the same dimension d.

According to the embodiment illustrated in FIG. 4, a light-emitting element in accordance herewith is provided as a thin wire 40 helically wrapped around a larger wire or similar support 41 connected into an electric current as by conductors 42.

As with the previously described embodiments, the diameter d of wire 40 is selected to approximate the wave length of the radiation desired, while the space between adjacent convolutions of wire 40 is also selected to be of the same dimension-eg., of the order of 1-2 microns to give high polarization in the optical light range. This structure as indicated in FIG. 4 may be particularly preferred in the manufacture of polarizing filaments for ncandescent lamps and particularly in view of its relationship to manufacturing techniques currently used for producing tiny spring-like helical filaments from tungsten or other very fine filament wire.

A further embodiment of a polarizing light-emitting element is illustrated in FIG. 5 as comprising a series of thin discs 51, 52, 53, etc., collected into an elongated element for connection to the source of electricity as by conductors S4. In this arrangement, every second disc (e.g., 51, 53, etc.) is selected from a material having an index of refraction differing from the index of refraction of the other discs by an amount which approximates the wave length of light desired to be emitted. In this connection, by refractive index is meant, as will be understood, the square root of the dielectric constant of the materials involved and describes the refraction of a plane electromagnetic wave passing through the surface into the material.

Satisfactory results in accordance with this embodiment have been achieved by forming the element of FIG. 5 from alternating stacked tungsten discs (51, 53, etc.) and molybdenum discs (52, etc.) alternately arranged, as well as with a plurality of copper discs separated by layers of silver and constructed as by having the copper discs silver brazed to each other, and with the tungsten or copper discs having axial thicknesses of approximately 0.6 micron. Similarly, instead of a difference in refractive index between alternating discs, satisfactory results are also achieved if alternate discs are provided with different diameters where the difference in diameter (satisfactorily at least greater than 0.05 micron) approximates the wave lengths of light radiation desired to be emitted. Also, as will be understood from the foregoing, this embodiment is also satisfactorily constructed with discs of metal alternating wits discs of semi-conductor materials, provided only that the differences in the refractive indexes of the materials chosen are related, as above noted, to the wave length of the polarized radiation desired.

In the embodiment of FIG. 6 there is illustrated an application of this invention to a conventional gas discharge tube indicated at 60 and having a glass envelope 61 with conductors and discharge elements 62 and 63 therein, all in known manner. Satisfactory results are obtained in the adaptation or utilization of such a gas discharge device in accordance with this invention by depositing an opaque metallic layer over the outside of envelope 61 (or, alternatively, on the inside surface thereof) and then scratching or otherwise providing in such metallic layer transparent grooves (circular or helical) to leave a helical (or circular) elongated and substantially continuous but spaced coating element 64 around envelope 61, with the several convolutions thereof spaced apart by transparent areas 65.

As will be apparent from the foregoing discussion, the

axial width of the metallic areas 64 (and preferably of the transparent areas 65 therebetween) approximates the wave length of the particular polarized radiation desired. Satisfactory results in accordance herewith are achieved with the deposited metallic layer, from which the several areas 64 are developed, being of plated or otherwise deposited metallic silver, for example, and with the dimension d being approximately 0.5 micron. In this arrangement, the energy obtained from the gas discharge tube 60 is absorbed in the metallic layers 64 (whether they are on the inside or the outside of transparent envelope 61) and transformed therein into characteristic radiation, which is re-radiated as strongly polarized light, while the spacing of the layers 64 and the relationship of the axial dimensions of the transparent portions therebetween directly polarize light generated within envelope 61 to the same direction.

Accordingly, and as will be apparent from the foregoing, there are provided herewith a variety of embodiments or forms for the direct generation or emission of strongly polarized light utilizing elongated light-emitting elements for electric and thermic energization to produce directly polarized radiation (both from the elongated elements themselves and, in some instances, from the supports therefor through spaces between adjacent sections of the primary elements), and all utilizing the full available energy from the electric source to produce polarized radiation directly without the conventional interposition of filters and other equipment which may curtail the total efficiency or emission potential of the particular energized source of radiation. Similarly, the various arrangements embodying or for practicing this invention are readily useful with conventional mirror and/ or lens systems, as may be desired, and forming the incandescent or light-generating filaments in incandescant lamps or as applied to gas discharge or other types of conventional light sources. Yet, in each case the light is initially generated in polarized form, merely in accordance with the proper selection of the element materials and/ or dimensioning the the various structures in accordance herewith, so that the total radiant emission or the light element or source is utilized without filtering out or wasting a portion thereof in order to obtain the desired polarized effect.

While the forms of apparatus disclosed herein form preferred embodiments of this invention, this invention is not limited to these precise forms of apparatus and modifications may be made therein without departing from the scope of this invention which is dened in the appended claims.

What is claimed is:

1. In a light-emitting device for inclusion as a light source in electric lamps and the like for the generation and production of radiation directly polarized into a single direction, the combination which comprises an elongated light-emitting and generating element, means for supporting said elongated element with continuous portions thereof in parallel side-by-side spaced arrangement with respect to other portions thereof, and means for electrically energizing and heating said element and said support means for producing thermic emission and light radiation therefrom, the transverse dimension of said elongated element in a direction perpendicular to the axis thereof being generally of the same order of magnitude as the wave-length of radiation emitted thereby, and the transverse dimension of said spacing between said parallel portions of said elongated element also being generally of the same order of magnitude as the wave-length of radiation emitted by said element.

2. In a light-emitting device for inclusion as a light source in electric lamps and the like for the generation and production of radiation directly polarized into a single direction, the combination which comprises an elongated light-emitting and generating element, means for supporting said elongated element with portions thereof in parallel side-by-side spaced arrangement with respect to other portions thereof, and means for electrically energizing and heating said element for producing thermic emission and light radiation therefrom, the transverse dimension of said elongated element in a direction perpendicular to the axis thereof being generally of the same order of magnitude as the wave-length of radiation emitted thereby, and the transverse dimension of said spacing between said parallel portions of said elongated element also being generally of the same order of magnitude as the Wave length of radiation emitted by said element.

3. In a light-emitting device for inclusion as a light source in electric lamps and the like for the generation and production of radiation directly polarized into a single direction, the combination which comprises an elongated light-emitting and generating element, means for supporting said elongated element with portions thereof in parallel side-by-side spaced arrangement with respect to other portions thereof, and means for electrically energizing and heating said element for producing thermic emission and light radiation therefrom,'the transverse dimension of said elongated element in a direction perpendicular to the axis thereof being generally of the same order of magnitude as the wave-length of radiation emitted thereby.

4. In a light-emitting device for inclusion as a light source in electric lamps and the like for the generation and production of radiation directly polarized into a single direction, the combination which comprises an elongated light-emitting and generating element, means for supporting said elongated element in said lamps, and means for electrically energizing and heating said element for producing thermic emission and light radiation therefrom, the transverse dimension of said elongated element in a direction perpendicular to the axis thereof being generally of the same order of magnitude as the wave-length of radiation emitted thereby, and the transverse dimension of said spacing between said parallel portions of said elongated elements also being generally of the same order of magnitude as the wave-length of radiation emitted by said element.

5. In a light-emitting device for inclusion as a light source in electric lamps and the like for the generation and production of radiation directly polarized into a single direction, the combination which comprises an elongated light-emitting and generating element, means for supporting said elongated element in said lamps, and means for electrically energizing and heating said element for producing thermic emission and light radiation therefrom, the transverse dimension of said elongated element in a direction perpendicular to the axis thereof being generally of the same order of magnitude as the wave-length of radiation emitted thereby.

6. A light-emitting device as recited in claim 5 in which said elongated element is formed as a plurality of spaced parallel ridges and said means for supporting said element is formed as a flat plate with said ridges on the surface thereof.

7. A light-emitting device as recited in claim 5 in which said means for supporting said elongated element is a generally cylindrical member and in which said elongated element is formed as a plurality of parallel spaced ridges on said cylindrical member.

8. A light-emitting device as recited in claim 5 in which said elongated light-emitting element is formed as a plurality of wires axed in spaced relation on the surface of said supporting means.

9. A light-emitting device as recited in claim 8 in which both the diameter of said wires and the transverse dimension of said spacing therebetween are approximately the same as the wave-length of radiation emitted thereby, and in which radiation is generated by said supporting means in the spaces between said wires as well as by said wires.

10. A light-emitting device as recited in claim 5 in which said means for supporting said elongated element is a filament wire and in which said elongated light-emitting element is a thin wire wound helically around said filament wire and in thermal and electrical conducting Contact therewith.

11. A light-emitting device as recited in claim l0 in which said filament wire is energized for thermic radiation emission and for heating said thin wire, and in which the spaces between adjacent convolutions of said helically wound thin Wire have a transverse dimension approximately equal to both the diameter of said thin wire and said Wave-length of radiation emitted thereby.

12. A light-emitting device as recited in claim 5 in which said light-emitting element is formed as the peripheral surface of a plurality of discs arranged in face-t0- face relation for also forming said supporting means, all of said discs having an axial thickness of generally the same order of magnitude as the wave-length of radiation emitted thereby, and every second one of said discs having a refractive index differing from the refractive index of the remainder of said discs by an amount generally of the same order of magnitude as the Wave-length of radiation emitted thereby.

13. A light-emitting device as recited in claim 12 in which all of said discs have substantially the same axial thickness.

14. A light-emitting device as recited in claim 5 in which said light-emitting element is formed as the peripheral surface of a plurality of discs arranged in face-toface relation for also forming said supporting means, all of said discs having an axial thickness of generally the same order of magnitude as the wave-length of radiation emitted thereby, and every second one of said discs having a diameter which differs from the diameter of the remainder of said discs by an amount approximately equal to the wavelength of radiation emitted thereby.

15. A light-emitting device as recited in claim 5 in which said means for electrically energizing and heating said element for producing thermic emission and light radiation is a gas discharge light source enclosed within a transparent glass envelope, which envelope forms said means for supporting said elongated element, and in which said elongated element is formed as spaced strips of metallic material disposed on the surface of said envelope for ther-mic energization by discharges Within said envelope, and in which the transverse dimension of both said strips and the spaces therebetween are generally of the same order of magnitude as the Wave-lengths of radiation emitted by said strips upon energization thereof.

16. A light-emitting device as recited in claim 5 in which said elongated light-emitting element comprises a plurality of parallel side by side spaced portions and References Cited by the Examiner UNITED STATES PATENTS 6/1942 Brown 88-65 3/1964 Kahn 88-65 10 JAMES W. LAWRENCE, Primary Examiner.

R. IUDD, Assistant Examiner. 

1. IN A LIGHT-EMITTING DEVICE FOR INCLUSION AS A LIGHT SOURCE IN ELECTRIC LAMPS AND THE LIKE FOR THE GENERATION AND PRODUCTION OF RADIATION DIRECTLY POLARIZED INTO A SINGLE DIRECTION, THE COMBINATION WHICH COMPRISES AN ELONGATED LIGHT-EMITTING AND GENERATING ELEMENT, MEANS FOR SUPPORTING SAID ELONGATED ELEMENT WITH CONTINUOUS PORTIONS THEREOF IN PARALLEL SIDE-BY-SIDE SPACED ARRANGEMENT WITH RESPECT TO OTHER PORTIONS THEREOF, AND MEANS FOR ELECTRICALLY ENERGIZING AND HEATING SAID ELEMENT AND SAID SUPPORT MEANS FOR PRODUCING THERMIC EMISSION AND LIGHT RADIATION 